1. Field
Aspects of the present disclosure relate generally to wireless communication systems, and more particularly, to improving control of device random access attempts.
2. Background
Wireless communication networks are widely deployed to provide various communication services such as telephony, video, data, messaging, broadcasts, and so on. Such networks, which are usually multiple access networks, support communications for multiple users by sharing the available network resources. One example of such a network is the UMTS Terrestrial Radio Access Network (UTRAN). The UTRAN is the radio access network (RAN) defined as a part of the Universal Mobile Telecommunications System (UMTS), a third generation (3G) mobile phone technology supported by the 3rd Generation Partnership Project (3GPP). The UMTS, which is the successor to Global System for Mobile Communications (GSM) technologies, currently supports various air interface standards, such as Wideband-Code Division Multiple Access (W-CDMA), Time Division-Code Division Multiple Access (TD-CDMA), and Time Division-Synchronous Code Division Multiple Access (TD-SCDMA). The UMTS also supports enhanced 3G data communications protocols, such as High Speed Packet Access (HSDPA), which provides higher data transfer speeds and capacity to associated UMTS networks.
As the demand for mobile broadband access continues to increase, research and development continue to advance the UMTS technologies not only to meet the growing demand for mobile broadband access, but to advance and enhance the user experience with mobile communications.
Consider a cellular system that supports a large number of user equipment (UEs). In such a setting, if a significant number of the UEs attempt to connect to a RAN component, such as a base station, in a short period of time, there could be congestion in the RAN due to the UEs performing a random access procedure. For example, if a cell contains 10,000 smart meters and a significant fraction of these attempt to connect to the base station in a short duration of time, this situation could lead to high blocking probability for the other UEs in the cell and could also lead to high interference (RoT) levels.
Some prior solutions have attempted to use a geometric backoff approach to delay the initial random access attempts of the UEs so as to avoid congestion (e.g. LTE Access Class Barring/UMTS Persistence Check). While the parameters for such backoff can be set so that the access attempts of the UEs can be effectively distributed, such an approach can lead to excessive delay for a small fraction of the devices. This happens because the tail of the geometric distribution has non-zero probability even at very large values. Since in some scenarios there are a large number of devices in the system, the small fraction that experience excessively large delays can be a significant number.
Accordingly, improvements are desired for controlling access to a communication network.